Balanced chemical reaction: 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g).
KOH is inorganic compound potassium hydroxide, a strong base.
H₂ is hydrogen gas.
In balanced chemical reaction number of atoms on both side of chemical reaction must be same. There are two potassium atoms, four hydrogen atoms and two oxygen atoms on both side of reaction.